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	<head>
		<title>three.js webgl - geometry - dynamic</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<link type="text/css" rel="stylesheet" href="main.css">
		<style>
			body {
				color: #666;
			}
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	<body>

		<div id="info">
			<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - dynamic geometry<br />
			left click: forward, right click: backward
		</div>

		<script type="module">

			import * as THREE from '../build/three.module.js';

			import Stats from './jsm/libs/stats.module.js';

			import { FirstPersonControls } from './jsm/controls/FirstPersonControls.js';

			let camera, controls, scene, renderer, stats;

			let mesh, geometry, material, clock;

			const worldWidth = 128, worldDepth = 128;

			init();
			animate();

			function init() {

				camera = new THREE.PerspectiveCamera( 60, window.innerWidth / window.innerHeight, 1, 20000 );
				camera.position.y = 200;

				clock = new THREE.Clock();

				scene = new THREE.Scene();
				scene.background = new THREE.Color( 0xaaccff );
				scene.fog = new THREE.FogExp2( 0xaaccff, 0.0007 );

				geometry = new THREE.PlaneGeometry( 20000, 20000, worldWidth - 1, worldDepth - 1 );
				geometry.rotateX( - Math.PI / 2 );

				const position = geometry.attributes.position;
				position.usage = THREE.DynamicDrawUsage;

				for ( let i = 0; i < position.count; i ++ ) {

					const y = 35 * Math.sin( i / 2 );
					position.setY( i, y );

				}

				const texture = new THREE.TextureLoader().load( 'textures/water.jpg' );
				texture.wrapS = texture.wrapT = THREE.RepeatWrapping;
				texture.repeat.set( 5, 5 );

				material = new THREE.MeshBasicMaterial( { color: 0x0044ff, map: texture } );

				mesh = new THREE.Mesh( geometry, material );
				scene.add( mesh );

				renderer = new THREE.WebGLRenderer( { antialias: true } );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				document.body.appendChild( renderer.domElement );

				controls = new FirstPersonControls( camera, renderer.domElement );

				controls.movementSpeed = 500;
				controls.lookSpeed = 0.1;

				stats = new Stats();
				document.body.appendChild( stats.dom );

				//

				window.addEventListener( 'resize', onWindowResize );

			}

			function onWindowResize() {

				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();

				renderer.setSize( window.innerWidth, window.innerHeight );

				controls.handleResize();

			}

			//

			function animate() {

				requestAnimationFrame( animate );

				render();
				stats.update();

			}

			function render() {

				const delta = clock.getDelta();
				const time = clock.getElapsedTime() * 10;

				const position = geometry.attributes.position;

				for ( let i = 0; i < position.count; i ++ ) {

					const y = 35 * Math.sin( i / 5 + ( time + i ) / 7 );
					position.setY( i, y );

				}

				position.needsUpdate = true;

				controls.update( delta );
				renderer.render( scene, camera );

			}

		</script>

	</body>
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